import { createServer } from "node:http";
import { readFile, stat } from "node:fs/promises";
import path from "node:path";
import { fileURLToPath } from "node:url";

const root = path.resolve(
  path.dirname(fileURLToPath(import.meta.url)),
  "..",
  "dist",
);
const nestedPrefix = "/deep/nested/helpers/";
const mediaTypes = new Map([
  [".css", "text/css; charset=utf-8"],
  [".html", "text/html; charset=utf-8"],
  [".js", "application/javascript; charset=utf-8"],
  [".json", "application/json; charset=utf-8"],
  [".md", "text/markdown; charset=utf-8"],
  [".svg", "image/svg+xml"],
  [".txt", "text/plain; charset=utf-8"],
  [".webmanifest", "application/manifest+json"],
]);
const headers = {
  "Content-Security-Policy":
    "default-src 'self'; script-src 'self'; style-src 'self'; img-src 'self' data: blob:; object-src 'none'; base-uri 'self'; form-action 'none'; frame-ancestors 'none'",
  "Cross-Origin-Opener-Policy": "same-origin",
  "Cross-Origin-Resource-Policy": "same-origin",
  "Permissions-Policy": "camera=(), microphone=(), geolocation=()",
  "Referrer-Policy": "no-referrer",
  "X-Content-Type-Options": "nosniff",
};

createServer(async (request, response) => {
  try {
    const url = new URL(request.url ?? "/", "http://127.0.0.1");
    if (!url.pathname.startsWith(nestedPrefix)) {
      response.writeHead(404, headers).end("Not found");
      return;
    }
    let relative = decodeURIComponent(url.pathname.slice(nestedPrefix.length));
    if (!relative || relative.endsWith("/")) relative += "index.html";
    if (relative.includes("\\") || relative.split("/").includes("..")) {
      response.writeHead(400, headers).end("Bad path");
      return;
    }
    const absolute = path.resolve(root, relative);
    if (
      !absolute.startsWith(`${root}${path.sep}`) ||
      !(await stat(absolute)).isFile()
    ) {
      response.writeHead(404, headers).end("Not found");
      return;
    }
    const body = await readFile(absolute);
    response.writeHead(200, {
      ...headers,
      "Content-Type":
        mediaTypes.get(path.extname(absolute)) ?? "application/octet-stream",
      "Cache-Control": relative.startsWith("assets/")
        ? "public, max-age=31536000, immutable"
        : "no-cache",
    });
    response.end(body);
  } catch {
    response.writeHead(404, headers).end("Not found");
  }
}).listen(4173, "127.0.0.1", () => {
  console.log(`Serving Helper Tools at http://127.0.0.1:4173${nestedPrefix}`);
});